Methods

Methods are written inside a class. Methods hold a block of instructions to carry out some task. Methods have an optional accessor (public, protected, private), a return type (void, int, double, String, etc.), an identifier (name), parenthesis and an optional parameter list (list of variables to receive values from the caller), a left brace to indicate the start of the code block, the code, and the end of the code block. All computer instructions must be wrapped up inside a method. All methods must be defined inside a class (between the left brace ( { ) and the right brace ( } ).

Accessor      return type      identifier (name)      ( optional parameter list )
{   // begin marker

         // computer instructions (code, commands, statements)

}    // end marker

Examples:


// The following MyPoint class holds the coordinates
// for a point on a 2D plane.

public class MyPoint {

    // instance variables 
    // storage is always available
    // for the life of an object of this type
    int x;
    int y;
    
	
    // constructor MyPoint with 2 parameters
    // this.x refers to the instance variable x
    // this.y refers to the instance variable x
    // x and y refer to the temporary parameter variables x and y
    // which only exist when the constructor is called (invoked)
    public MyPoint(int x, int y)    
    {
        this.x = x; 
        this.y = y;
    }
    
    // method getX() will return an int
    // which is the value of the instance variable x
    // we do not need to say this.x because there is no local variable x
    // this is called a getter method since it returns the value of an instance variable
    public int getX()
    {
        return x;   // or we could say   return this.x;
    }
 
    // method setX(int x) does not return a value
    // it receives a value and then assigns that value to the instance variable x
    // this is called a setter method since it sets the value of an instance variable
    public void setX(int x)
    {
        this.x = x;
    }   
	
    // other methods not shown

}